Abstract

Compositional dependence of the conduction‐band discontinuity ΔEc in InxGa1−xAs/In0.52Al0.48As pseudomorphic heterostructures has been measured as a function of InAs mole fraction over the range of 0.44≤x≤0.64 using both current‐versus‐voltage‐versus‐temperature and capacitance‐versus‐voltage measurements on semiconductor‐insulator‐semiconductor structures. The results show a monotonic increase of effective ΔEc with InAs mole fraction x according to ΔEc≊0.384+0.254x for x≤0.54 and an abrupt shift to ΔEc≊0.344+0.487x for x≥0.58. The effects of the conduction‐band nonparabolicity and the lattice strain on the Fermi potential have been taken into account in deducing ΔEc from the measured barrier height across the InxGa1−xAs/In0.52Al0.48As heterojunction.